Issued also as a Sc.D. thesis in the Dept. of Electrical Engineering, 1968. / Bibliography: p.103-104.

ESD-TR-67-466. / Bibliography: p.85. / Contract AF 19(628)-5167.

Reprinted from IEEE transactions on information theory, vol. IT-13, no.3, July 1967. / Bibliography: p. 501.

Based on a thesis in Electrical Engineering, 1966. / Bibliography: p.109-110. / Contract no. DA36-039-AMC-03200(E).

No description available.

Includes bibliographies.

Thesis (Ph. D.)--University of Texas at Austin, 2006. / Vita. Includes bibliographical references.

Not available / text

Fluctuation phenomena are important to many physical systems, such as the fusion plasma. Noise theory is used to study the time and space correlations of stationary Markovian fluctuations that are statistically homogeneous and isotropic. The relaxation of the fluctuations is modeled by the diffusion equation. The spatial correlations are modeled by the exponential decay. Based on these models, the correlation function and the power spectral density of random fluctuations. We also find that the fluctuation-induced transport coefficients may be estimated by the correlation length and the correlation time. The theoretical results are compared with the observed plasma density fluctuations from tokamak and helimak experiments.

In present day wireless applications, especially for time-varying channels, we require flexible coding schemes that utilize a minimum of bandwidth and can support different code rates. In addition, we require coding schemes that are simple in terms of complexity but give good performance. Recently a special class of turbo-like codes called repeat accumulate (RA) codes were proposed. These codes are extremely simple in terms of complexity compared to turbo or LDPC codes and have been shown to have decoding thresholds close to the capacity of the AWGN channel. In this thesis, we propose rate-compatible punctured systematic RA codes for the additive white Gaussian noise (AWGN) channel. We first pro-pose a three phase puncturing scheme that provides rate compatibility and show that very high rate code rates can be obtained from a single mother code. We then provide a methodology to design rate-compatible RA codes based on our three phase puncturing scheme. The design involves optimizing the punctured profile of the code such that the resulting high rate codes give good performance. The design is done with the help of existrinsic in-formation transfer (EXIT) charts which are plots used to analyze the constituent decoders. Code rates up to 10/11 are obtained from a single rate 1/3 regular RA code. Performance results show that our design methodology combined with our proposed puncturing scheme can provide significant coding gains at high code rates even with practical blocklengths. Hence rate-compatible punctured RA codes are suitable for many wireless applications.